锚链坠落及碰撞的数值模拟

Numerical Simulation of Drop and Collision of Anchor Chain

锚链脱落坠入海底的事故时有发生,分析锚链坠落后的完整性对打捞工作有实际的工程意义.基于OrcaFlex海洋工程软件,应用质量-弹簧模型数值模拟锚链坠落问题,结合冲击函数法,分析坠落过程中链环间的碰撞.研究结果表明,链环间碰撞应力大小主要取决于锚链初始姿态,锚链与海床倾角越大,链环间发生危险碰撞概率越大,碰撞应力也越大.同时采用有限元软件模拟2环碰撞,相比于锚链整体模型,2环相撞是多环锚链坠落碰撞的一种简化模型.通过比较2环碰撞与多环碰撞应力大小,验证了多环碰撞计算结果的可靠性.

Accidents of anchor chain dropping into the sea occur from time to time, and it has a practi- cal significance to analyse the integrity of the chain for salvage work. Based on mass-spring model, line clash model in OrcaFlex software, this paper analyses the falling process with focuses on the colli- sion between links. It turns out that there is a strong correlation between collision stress and initial configuration of the chain. The greater the angle between the chain and seabed, the greater probabili ty of dangerous collision between links, and the lager stress of collision. Additionally, FEM software is used to simulate collision between two links, which is a simplification of entire chain. By comparing the stress of two links＇ collision with those of rnultiqink collision, the reliability of the results of multiqink collision is verified.